The invention involves a lamp, in particular a lamp for medical applications, having at least one source for light emission, at least two reflectors, where in order to form a low-shadow illuminated area, light emerging from the lamp impinges upon the illuminated area by at least two different angles of incidence.
From the patent GB-PS 1 537 181, a lighting devicexe2x80x94in particular an operating lampxe2x80x94is known, which for the purpose of uniform illumination of the operating area, has several light beams emerging from one light source. The light beams are directed at each of two deflection mirrors arranged in a lamp arm. In this way, one part of each light beam is reflected by an inner deflection mirror and the other part is transmitted to an outer deflection mirror. The slope of the deflection mirror is adjustable in relation to the horizontally running axis of the original light beam. Thus, two light beams, which are directed at the area to be illuminated and are convertible, emerge from each lamp arm. However, the possibility of adjustment with regard to an expansion of the illuminated area or an adjustment of the depth of shadow is not provided here.
In addition, from EP 0 299 196 B1, a operation lamp having at least two separate light beams emerging from different areas of the bottom of the lamp housing is known. The optical axes of the light beams are directed onto an operating area in such a way by at least one adjustment component, that the light beams become superimposed while forming an intensified area of illumination. However, in this arrangement, the setting of an intense illumination of depth, as is necessary, for example, for deep operation wounds, can only be achieved by enlarging the separation distance of the operating lamp, where the intensity of the light as well as the angle of incidence of the individual light beams is reduced and thus approach the housing axis when the separation distance is enlarged.
Furthermore, from DE 25 19 426 A1, a lighting device for a hospital is known that has several lamps which are arranged such that their light axes converge at a focal point so that through adjustment using a lamp guide device, the focal point can be shifted within a plane or perpendicular to a plane in the desired manner. This device involves a relatively expensive construction.
The purpose of the invention presented here is to create a lamp for forming a low-shadow illuminated area, in which light or light beams emerging from the lamp impinge upon the illuminated area at different angles of incidence, so that both an intense wide illumination as well as a low-shadow depth illumination is possible in the illuminated area itself. In particular, the depth of shadow should be adjustable, as can be necessary especially when using a lamp of this type for medical applications for deep wounds.
Furthermore, as compact a shape of the lamp as possible should be obtained. The shape should allow the lamp to be integrated into existing lighting systems, e.g. for the operating room, in a simple way.
This purpose is achieved in that the angle of incidence of the light can be adjusted by changing the distance between at least two reflectors or between one reflector and the source of the light.
In a preferred embodiment form of the lamp, at least two reflectors are arranged so that they can shift in the radial direction on carrier arms that extend radially from the center of the lamp. In this manner, all reflectors always lie on a common circular circumference, and the reflectors can be shifted through manually activated gears or through electric drive motors.
The operating distance between lamp and wound is preferably in the range from 800 to 1200 mm; the optimal working distance is approx. 1000 mm. The optimal shifting path of the reflectors along the carrier axis lies in the range from 100 to 150 mm. It is thus possible in an advantageous manner to obtain an optimal rear illumination of obstructions in the beam path of the individual lamps.
Proving to be especially advantageous is the simple adjustability between the width illumination and the depth illumination. Furthermore, it proves to be advantageous that both discharge lamps and also spiral-wound filament lamps are suitable for use in the lamp according to the invention.
In an additional preferred embodiment of the lamp, two ring-shaped reflectors are provided coaxially to the lamp-longitudinal axis, where an outer ring-reflector surrounds the light source arranged in the longitudinal axis of the lamp, while on the side that faces away from the illuminated area, an inner ring-reflector is provided. The inner ring-reflector is arranged so that it can shift along the longitudinal axis. The inner ring-reflector can be shifted so far that the outer ring-reflector can be shaded by it so that an intense depth illumination is obtained.
The simple constructive design proves to be advantageous.
In a similarly constructed embodiment of the lamp, the light source is arranged so that it can shift along the longitudinal axis.
Because the reflectors are arranged locationally fixed to each other, a relatively simple mechanical design of the lamp results so that in an advantageous way, a low-maintenance operation is obtained along with a cost-effective manufacturing.
Proving to be especially advantageous is the greatly reduced shadow formation in the illuminated area as compared to traditional lamps allowing use as an operation lamp.
The lamp can thus be universally adapted to the respective operation. In the case of small, deep wounds, the surgeon prefers a lot of light from the lamp center. In the case of large-area, flat wounds, a smaller shadow formation results, since obstructions are illuminated from behind by light from the edge. The light incident at a slant angle improves the three-dimensional visibility for the surgeon.
In the following, the object of the invention is explained in greater detail using the FIGS. 1a, 1b, 2a, 2b, 2c, 3a, 3b and 3c.